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United States Patent |
6,099,800
|
Cheng
|
August 8, 2000
|
Process for cleaning and disinfecting contact lens and hydrogen peroxide
destroying composition having a delayed release function for use therein
Abstract
A hydrogen peroxide destroying composition is disclosed, which includes
1-30% of a hydrogen peroxide destroying component, 0.5-40% of a binder,
0-20% of a disintegrant and 0.02-3% of a chlorophyll coloring agent, based
on the weight of the hydrogen peroxide destroying composition. When the
hydrogen peroxide destroying composition of the present invention in the
form of a tablet or pills added into a H.sub.2 O.sub.2 -containing aqueous
medium for disinfecting contact lens, said coloring agent will color the
aqueous medium indicating an initiation of neutralization of residual
H.sub.2 O.sub.2 caused by the hydrogen peroxide destroying component after
a period of time from the addition.
Inventors:
|
Cheng; Hui-Wen (Taipei, TW)
|
Assignee:
|
Sinphar Pharmaceutical Co., Ltd. (I-Lan, TW)
|
Appl. No.:
|
134160 |
Filed:
|
August 14, 1998 |
Current U.S. Class: |
422/30; 252/188.21 |
Intern'l Class: |
A61L 012/12 |
Field of Search: |
422/30
252/188.21,363.5
|
References Cited
Foreign Patent Documents |
86/05695 | Oct., 1986 | WO.
| |
93/04706 | Mar., 1993 | WO.
| |
Primary Examiner: McKane; Elizabeth
Attorney, Agent or Firm: Bacon & Thomas
Claims
What is claimed is:
1. A process for cleaning and disinfecting contact lens comprising
immersing the contact lens in a predetermined volume of a H.sub.2 O.sub.2
-containing aqueous medium; and immediately followed by or simultaneously
adding one or a plurality of tablets or pills into the H.sub.2 O.sub.2
-containing aqueous medium, wherein said tablets or pills have a hydrogen
peroxide destroying composition comprising 1-30% of a hydrogen peroxide
destroying component, 0.5-40% of a binder, 0-20% of a disintegrant and
0.02-3% of chlorophyll as a coloring agent, based on the weight of the
hydrogen peroxide destroying composition, wherein said chlorophyll
coloring agent will color the aqueous medium indicating an initiation of
neutralization of residual H.sub.2 O.sub.2 caused by the hydrogen peroxide
destroying component after a period of time from the addition.
2. The process according to claim 1, wherein said hydrogen peroxide
destroying component is selected from the group consisting essentially of
thiosulfates, sulfites, alkali metal salts, thiourea, ascorbic acid,
iso-ascorbic acid, N-acetylcysteine, glyoxylic acid, peroxidase, catalase
and mixtures thereof.
3. The process according to claim 2, wherein said hydrogen peroxide
destroying component is a catalase or a mixture containing catalase.
4. The process according to claim 1, wherein said H.sub.2 O.sub.2
-containing aqueous medium is maintained at a pH value ranging from about
5 to about 9 after the contact lens and the tablets or pills are immersed
therein.
5. A hydrogen peroxide destroying composition comprising 1-30% of a
hydrogen peroxide destroying component, 0.5-40% of a binder, 0-20% of a
disintegrant and 0.02-3% of chlorophyll as a coloring agent, based on the
weight of the hydrogen peroxide destroying composition.
6. The composition according to claim 5, wherein said hydrogen peroxide
destroying component is selected from the group consisting essentially of
thiosulfates, sulfites, alkali metal salts, thiourea, ascorbic acid,
iso-ascorbic acid, N-acetylcysteine, glyoxylic acid, peroxidase, catalase
and mixtures thereof.
7. The composition process according to claim 6, wherein said hydrogen
peroxide destroying component is a catalase or a mixture containing
catalase.
8. The composition according to claim 5, wherein the content of said
chlorophyll is 0.1-2.0% based on the weight of the hydrogen peroxide
destroying composition.
Description
FIELD OF THE INVENTION
The present invention is related to a hydrogen peroxide destroying
composition having a delayed release function for use in a contact lens
one-step cleaning and disinfecting process. In particular, the present
invention is related to a hydrogen peroxide destroying composition which
has a function of delayed releasing a hydrogen peroxide destroying
component contained therein and a function of showing a sign of an
initiation of neutralization of residual H.sub.2 O.sub.2 caused by the
hydrogen peroxide destroying component.
BACKGROUND OF THE INVENTION
Contact lenses should be periodically cleaned and disinfected by the user
to prevent infection or other deleterious effects on ocular health which
may be associated with contact lens wear. Currently, there are several
different conventional systems and methods which enable the user to clean
and disinfect their contact lenses between wearing times. These
conventional cleaning and disinfection systems can be divided into "hot"
and "cold" systems. Hot systems require the use of heat to disinfect the
contact lenses, whereas cold Systems use chemical disinfectants at ambient
temperatures to disinfect the lenses.
Within the realm of cold disinfection systems are hydrogen peroxide
disinfection systems. Disinfecting hydrogen peroxide solutions are
effective to kill the bacteria and fungi which may contaminate contact
lenses, however, residual hydrogen peroxide on a disinfected contact lens
may cause irritation, burning or trauma to the eye unless this hydrogen
peroxide is destroyed, i.e., decomposed, neutralized, inactivated or
chemically reduced. Therefore, the destruction of the residua hydrogen
peroxide in the liquid medium containing the disinfected contact lens is
needed to enable safe and comfortable wear of the disinfected contact
lens.
Contact lenses can be cleaned by enzymatic action. For example, Huth, et al
U.S. Pat. No. RE. 32,677 discloses the simultaneous cleaning and
disinfecting of contact lenses by a method which comprises contacting the
lenses with a solution comprising a disinfecting amount of peroxide and an
effective amount of peroxide-active proteolytic enzyme for a time
sufficient to remove substantially all protein accretions and to disinfect
the lenses. This patent further discloses that catalyze organic enzymes
which catalyze the degradation of per-oxides, can be incorporated into
tablets and powder, particularly in time-release form both the proteolytic
enzyme and the catalyze should have high activity to provide a highly
effective degree of cleaning and peroxide degradation, respectively.
Associated with the problem of hydrogen peroxide destruction in contact
lens disinfection systems are the problems of easy use and user
compliance. To enhance user compliance and ease of use, several efforts
have focused on one-step disinfection and hydrogen peroxide destruction.
In this regard, various time release tablets containing a core tablet and
a totally soluble or insoluble coating have been suggested. Typical
examples can be found in U.S. Pat. Nos. 4,568,517; 4,767,559; and
5,145,644.
The tablet having a barrier coating described in the above-mentioned prior
art suffers the following disadvantages:
1. A complicated manufacturing process which requires a tableting procedure
to form a naked tablet and a coating procedure for forming a barrier layer
on the naked tablet;
2. A relatively high manufacturing cost; and
3. The tablet is vulnerable during manufacturing, transportation and
storage so that pinholes and/or cracks are formed on the barrier coating,
and thus the delayed release function is adversely affected or lost.
The primary objective of the present invention is to provide a hydrogen
peroxide destroying composition which does not have the aforesaid
drawbacks of the prior art.
A further objective of the present invention is to provide a hydrogen
peroxide destroying composition which has a function of delayed releasing
a hydrogen peroxide destroying component contained therein and a function
of showing a sign of an initiation of neutralization of H.sub.2 O.sub.2
caused by the hydrogen peroxide destroying component.
SUMMARY OF THE INVENTION
In order to accomplish the above objectives a hydrogen peroxide destroying
composition prepared in accordance with the present invention comprises
1-30% of a hydrogen peroxide destroying component, 0.5-40% of a binder,
0-20% of a disintegrant and 0.02-3%, preferably 0.1-2.0%, of a coloring
agent, based on the weight of the hydrogen peroxide destroying
composition. When the hydrogen peroxide destroying composition of the
present invention is added into a H.sub.2 O.sub.2 -containing aqueous
medium, said coloring agent will color the aqueous medium indicating an
initiation of neutralization of H.sub.2 O.sub.2 caused by the hydrogen
peroxide destroying component after a period of time from the addition.
The present invention also discloses a process for one-step cleaning and
disinfecting contact lens comprising placing the contact lens into a
H.sub.2 O.sub.2 -containing aqueous medium; and simultaneously adding one
or a plurality of tablets or pills into the H.sub.2 O.sub.2 -containing
aqueous medium, wherein said tablets or pills have a hydrogen peroxide
destroying composition comprising 1-30% of a hydrogen peroxide destroying
component, 0.5-40% of a binder, 0-20% of a disintegrant and 0.02-3%,
preferably 0.1-2.0%, of a coloring agent, based on the weight of the
hydrogen peroxide destroying composition. Preferably, said H.sub.2 O.sub.2
-containing aqueous medium is maintained at a pH value ranging from about
5 to about 9 after the contact lens and the tablets or pills are immersed
therein.
The hydrogen peroxide destroying composition of the present invention is
preferably in the form of a tablet or pill, which can be formed by a
conventional one-step tableting process with a reduced manufacturing cost.
Moreover, the risk of losing the delayed release function caused by pin
holes and/or cracks on the barrier coating of the conventional hydrogen
peroxide destroying composition in the coated tablet form can be avoided
in the present invention, because the hydrogen peroxide destroying
composition of the present invention in the form of a tablet or pill have
a substantially uniform composition and are free of the barrier coating.
DETAILED DESCRIPTION OF THE INVENTION
The present invention discloses a hydrogen peroxide destroying composition
having a delayed release function for use simultaneously with a H.sub.2
O.sub.2 -containing aqueous liquid medium to clean and disinfect contact
lens at ambient temperatures.
The hydrogen peroxide destroying composition of the present invention
comprises 1-30% of a hydrogen peroxide destroying component; 0.5-40%,
preferably 1-25%, and more preferably 2.5-10%, of a binder; 0-20%,
preferably 0-5%, and more preferably 0-2%, of a disintegrant; and 0.02-3%
of a coloring agent, based on the weight of the hydrogen peroxide
destroying composition.
Preferably, said coloring agent is chlorophyll.
Said hydrogen peroxide destroying component can be any compounds known in
the art which decompose neutralize, inactivated or chemically reduce the
hydrogen peroxide, such as enzymes, catalases and reducing agents.
Preferably, it is selected from the group consisting essentially of
thiosulfates, sulfites, alkali metal salts, thiourea, ascorbic acid,
iso-ascorbic acid, N-acetylcysteine, glyoxylic acid, peroxidase, catalase
and mixtures thereof. Among them catalase and mixtures containing catalase
are the most preferable.
Suitable binders for use in the present invention include any known
pharmaceutical binders used in forming a tablet and soluble in water.
Typical examples include (but not limited to) polyvinyl acetate, polyvinyl
pyrrolidone, polyvinyl alcohol, cellulose ethers, the derivatives thereof,
and the mixtures thereof.
The disintegrant of the composition of the present invention can be any
known pharmaceutical disintegrants for use in tableting. The content of
disintegrant in the composition of the present invention depends on the
recipe of the H.sub.2 O.sub.2 -containing aqueous liquid medium, and
increases as the H.sub.2 O.sub.2 concentration of the H.sub.2 O.sub.2
-containing aqueous liquid medium increases. The disintegrant can be
omitted from the composition of the present invention, if a long
delayed-release function is required due to a low H.sub.2 O.sub.2
concentration of the H.sub.2 O.sub.2 -containing aqueous liquid medium.
The hydrogen peroxide destroying composition of the present invention is in
the form of a tablet or pill, which can be prepared by a conventional
one-step tableting process. The tablet or pill should have a hardness
greater than about 5 Kg, preferably greater than 8 Kg, and more preferably
greater than 10 Kg. Moreover, the brittleness of the tablet or pill should
not less than 1%. The hardness of greater than 5 Kg and brittleness
greater than 1% are essential for the tablet or pill of the hydrogen
peroxide destroying composition of the present invention to have a desired
delayed-release function. The tablet or pill form of the present hydrogen
peroxide destroying composition have a substantially uniform composition,
and will break down and release the hydrogen peroxide destroying component
after a period of time starting from the cleaning and the disinfecting
process, so that any residual H.sub.2 O.sub.2 can be destroyed. The
coloring agent will also be released at the same time and thus color the
H.sub.2 O.sub.2 -containing aqueous liquid medium, indicating an
initiation of neutralization of H.sub.2 O.sub.2 (decomposing of H.sub.2
O.sub.2) caused by the hydrogen peroxide destroying component.
The H.sub.2 O.sub.2 -containing aqueous liquid medium is available from the
market. The amount of H.sub.2 O.sub.2 contained in the commercially
available H.sub.2 O.sub.2 -containing aqueous liquid mediums should be
sufficient to reduce at least 90% of microbe within 3 hours, preferably
within one hour, and most preferably within 10minutes starting from the
cleaning and disinfecting process. Alternatively, any compounds which can
produce H.sub.2 O.sub.2 in-situ can be used to replace the H.sub.2 O.sub.2
-containing aqueous liquid medium. These compounds, for example sodium
peroxide and peracetic acid, can be liquid, powder, or tablet. A contact
lens cleaning and disinfecting liquid medium can be prepared with these
compounds by diluting or dissolving with water.
The amount of the hydrogen peroxide destroying component contained in the
hydrogen peroxide destroying composition ideally is equivalent to a
stoichiometric amount for destroying a residual hydrogen peroxide
completely in the cleaning and disinfecting process. Taking catalase as an
example, 100-250 I.U. catalase per ml of 1 vol % H.sub.2 O.sub.2 aqueous
solution is a suitable concentration for destroying the H.sub.2 O.sub.2
completely, and 150-200 catalase per ml of 1 vol % H.sub.2 O.sub.2 aqueous
solution is more preferable. Therefore, once the content of the hydrogen
peroxide destroying component contained in the hydrogen peroxide
destroying composition is fixed, the amount of the hydrogen peroxide
destroying composition used is subjected to change by taking the amount of
the H.sub.2 O.sub.2 -containing aqueous liquid medium used and its H.sub.2
O.sub.2 concentration into consideration.
Additionally, any known pharmaceutical diluents and lubricants used in
forming a tablet can be incorporated to the hydrogen peroxide destroying
composition of the present invention. The amount of the diluent
incorporated varies from 10 wt % to 90 wt % based on the weight of the
composition and mainly depends on a desired content of the hydrogen
peroxide destroying component. Preferably, the amount of the diluent used
is 15-60 wt %, and more preferably ranging from 30-50 wt % based on the
weight of the composition. The lubricant is used as a fluidizing aid
during the tableting.
The hydrogen peroxide destroying composition of the present invention may
further comprise cleaning agents for contact lens, wetting/conditioning
agents for contact lens, tonicity agents for contact lens, effervescent
reagents for contact lens, wetting/conditioning agents for contact lens
and a pH buffer. The wetting/conditioning agents for contact lens are able
to enhance the wettability and preservability. The tonicity agents for
contact lens are able to adjust the osmosis pressure between the contact
lens and the eyes.
A typical effervescent reagent for use in the present invention is sodium
hydrogen carbonate. The effervescent reagent has a function to accelerate
the break down of the hydrogen peroxide destroying tablet or pill of the
present invention, and has a function to enhance the cleaning effect.
These are because the effervescent reagent produces carbon dioxide while
dissolving in the H.sub.2 O.sub.2 -containing liquid medium, creating
turbulent flows therein, so that accelerate the mixing of components in
the liquid medium, and thus enhance the break down of the tablet and the
cleaning of the dirt adhered on the contact lens.
The pH buffer is to adjust the pH value of the final liquid medium after
the cleaning and disinfecting process is finished. Any pH buffers able to
maintain the final liquid medium at a pH value ranging from 5 to 9 can be
used in the present invention such as phosphates and borates, in which the
compounds per se having a disinfecting ability are preferable such as
borates.
The tablet or pill of the hydrogen peroxide destroying composition of the
present invention are designed to break down and release the hydrogen
peroxide destroying component at a time when the cleaning and disinfecting
process is substantially finished. The cleaning and disinfecting process
may take 5 minutes up to 12 hours, generally from 10 to 20 minutes,
depending on the H.sub.2 O.sub.2 concentration of the H.sub.2 O.sub.2
-containing aqueous liquid medium. Accordingly, the tablet or pill of the
hydrogen peroxide destroying composition of the present invention will
break down and release the hydrogen peroxide destroying component at a
time ranging from 5 minutes to 12 hours after the cleaning and
disinfecting process is started. Moreover, the tablet or pill of the
hydrogen peroxide destroying composition of the present invention are
designed to completely decompose the residual hydrogen peroxide within 8
hours, preferably within 2 hours, and more preferably within 30 minutes.
These can be done by adjusting the formulation of the hydrogen peroxide
destroying composition of the present invention. The content of the binder
is decreased and the content of the disintegrant is increased when the
tablet or pill of the hydrogen peroxide destroying composition of the
present invention require a fast delayed-release, and vise versa. The
content of the hydrogen peroxide destroying component is approximately
counter-proportional to the time for completely decomposing the residual
hydrogen peroxide.
The present The invention will be further illustrated by the following
examples. The following examples are only meant to illustrate the
invention, but not to limit it.
EXAMPLE 1
A table was formed by using the following formula:
______________________________________
Catalase 3500 I.U.
Sodium phosphate, tribasic
1.2 mg
Mannitol 52.0 mg
Hydroxylpropylmethyl cellulose (HPMC)
26.2 mg
Polyethylene glycol (PEG 6000)
20.0 mg
Chlorophyll 0.6 mg.
______________________________________
To 10 ml of a commercially available H.sub.2 O.sub.2 -containing (3%)
contact lens disinfecting liquid medium in a contained the tablet prepared
above was added. The H.sub.2 O.sub.2 concentration of the resulting
mixture was measured with a test paper sold under a code of Merckoquant
1.10011.0001 by Merck company (Germany). The results are shown as follows:
______________________________________
Time (minutes)
H.sub.2 O.sub.2 Conc. (ppm)
______________________________________
0 30000
15 12500
30 5000
60 500
90 2
120 0.2
240 0
______________________________________
It can be seen from the above data that the tablet prepared according to
The present invention does have a delayed-release function, and the
delayed release time is about 4-5 hours.
EXAMPLE 2
Two tablets were prepared and the delayed release function of the tablets
were determined by repeating the procedures in Example 1 except that the
amount of catalase was replaced by those listed below:
______________________________________
Time when H.sub.2 O.sub.2 Conc. reaches
Catalase, I.U.
0 ppm, hours
______________________________________
2000 12-16
3500 4-5
______________________________________
The data shown above indicate that the H.sub.2 O.sub.2 concentration of the
resulting mixture takes a much shorter time to reach 0 ppm as the content
of the catalase in the composition increases.
EXAMPLE 3
A tablet was formed by using the following formula:
______________________________________
Catalase 3500 I.U.
Hydroxylpropylmethyl cellulose (HPMC)
33.8 mg
Sodium phosphate, tribasic
1.8 mg
Sorbitol 67.4 mg
Polyvinyl pyrrolidone 6.5 mg
Chlorophyll 0.5 mg.
______________________________________
The delayed release function of the tablet was determined by repeating the
procedures in Example 1. The results shown this tablet has a delayed
release time of 10 minutes and the H.sub.2 O.sub.2 concentration of the
resulting mixture reaches 0 within 240 minutes.
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